This invention relates to an optical disk apparatus and a disk identification method, or in particular, an optical disk apparatus for reproducing plural types of optical disks.
In the conventional technique finding wide application to an optical disk apparatus for reproducing the information from plural types of optical disks such as CD (Compact Disk) and DVD (Digital Versatile Disk), the type of the optical disk is identified based on the signal of the light reflected from the optical disk to which the light is radiated from an optical pickup.
This technique for identifying the type of the optical disk uses, for example, a method based on a signal of a focus error (focus error signal) obtained by driving the lens of the optical pickup in the direction toward the optical disk and an error signal of the total amount of light (pull-in error signal) of the optical pickup and a predetermined threshold value, or a method in which the sector mark of the optical disk is detected and the type of the optical disk is identified based on the position at which the sector mark is detected.
According to the technique for detecting the sector mark disclosed in JP-A-6-150563, for example, a gate signal is generated from the timing signal based on a pulse signal read from an optical disk, and the width of this gate signal is matched with each match data set by measurement at a predetermined frequency and appropriately changed, so that the sector mark of a different bit rate is excluded from the matching value and the sector mark length data, thereby identifying and detecting a corresponding sector mark.